In the production process of semiconductor devices such as IC and LSI, fine processing has been conventionally performed using a resist composition or by lithography. In recent years, accompanying higher integration of integrated circuits, formation of an ultrafine pattern in the sub-micron or quarter-micron region is being demanded. Along with this requirement, the exposure wavelength is becoming shorter, for example, changing from g line to i line or even to KrF excimer laser light. Furthermore, studies on lithography using electron beam, X ray or EUV light other than excimer laser light are proceeding at present.
Particularly, the electron beam lithography is expected as a next-generation or second next-generation pattern forming technique and a high-sensitivity and high-resolution resist is being demanded.
As the resist suitable for such an electron beam or X-ray lithography process, a chemical amplification-type resist utilizing mainly an acid catalytic reaction is used from the standpoint of attaining higher sensitivity.
Various studies have been heretofore made to improve the performance of chemical amplification-type resist and particularly, from the aspect of acid generator, the following studies have been made. For example, JP-B-8-3635 (the term “JP-B” as used herein means an “examined Japanese patent publication”) discloses organic halogen compounds, JP-A-2-52348 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) discloses aromatic compounds substituted by Br or Cl, JP-A-4-367864 and JP-A-4-367865 disclose aromatic compounds having an alkyl or alkoxy group substituted by Br or Cl, JP-A-3-87746 discloses haloalkane sulfonate compounds, JP-A-6-199770 discloses iodonium or sulfonium compounds, Japanese Patent 2,968,055 discloses trifluoromethane-sulfonate compounds having a phenolic hydroxy group, and JP-A-2001-142200 discloses specific benzenesulfonate compounds having a phenolic hydroxy group.
However, any combination of these compounds fails in satisfying both good pattern profile in the ultrafine region and good isolation performance.